Chapter 140. Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria (Part 2) ppsx

Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria Part 2 Kingella kingae Because of improved microbiologic methodology, isolation of K.. kingae has been the t

Chapter 140 Infections Due to the HACEK Group

and Miscellaneous Gram-Negative Bacteria

(Part 2)

Kingella kingae

Because of improved microbiologic methodology, isolation of K kingae is

increasingly common Inoculation of clinical specimens (e.g., synovial fluid) into aerobic blood culture bottles enhances recovery of this organism In recent series,

K kingae has been the third most common cause of septic arthritis in children <24

months of age; staphylococcal and streptococcal species remain most prevalent

Invasive K kingae infections with bacteremia are associated with upper respiratory tract infections and stomatitis Both K kingae colonization and primary herpes—a major cause of stomatitis—peak in children 6–48 months of age K

kingae bacteremia can present with a petechial rash similar to that seen in Neisseria meningitidis sepsis

Infective endocarditis, unlike other infections with K kingae, occurs in

older children and adults The majority of patients have preexisting valvular disease There is a high incidence of complications, including arterial emboli,

cerebrovascular accidents, tricuspid insufficiency, and congestive heart failure with cardiovascular collapse

Endocarditis Caused by HACEK Organisms: Treatment

See Table 140-1 Native-valve endocarditis should be treated for 4 weeks with antibiotics, whereas prosthetic-valve endocarditis requires 6 weeks of therapy The cure rates for HACEK prosthetic-valve endocarditis appear to be high Unlike prosthetic-valve endocarditis caused by other gram-negative organisms, HACEK endocarditis is often cured with antibiotic treatment alone— i.e., without surgical intervention

Table 140-1 Treatment of Endocarditis Caused by HACEK Group Organismsa

Organism Initial

Therapy

Alternative Agents Commen

ts

Haemophilus

species,

Actinobacillus

actinomycetemcomita

Ceftriaxo

ne (2 g/d)

Ampicillin/sulbact

am (3 g of ampicillin

fluoroquinolonesb

Ampicill

in ± an aminoglycoside can be used if

ns the organism

does not produce β-lactamase.c

Cardiobacteriu

m hominis

Penicillin (16–18 mU/d in

6 divided doses)

or ampicillin (2

g q4h)

Ceftriaxone (2

ampicillin/sulbactam (3 g

of ampicillin q6h)

An aminoglycoside (gentamicin, 3 mg/kg per day

in 3 divided doses) may be added, but its value has not been proven The organism is usually

pansensitive, but high-level penicillin

resistance has

been reported

Eikenella

corrodens

Ampicilli

n (2 g q4h)

Ceftriaxone (2

g/d) or fluoroquinolonesb

The organism is typically

resistant to clindamycin, metronidazole, and

aminoglycoside

s

Kingella

kingae

Ceftriaxo

ne (2 g/d) or ampicillin (3 g q6h)

Fluoroquinolonesb

The prevalence of β-lactamase-producing strains is increasing Efficacy for invasive

infections is

best demonstrated for first-line treatments

a

Susceptibility testing should be performed in all cases to guide therapy

b

Fluoroquinolones are not recommended for treatment of children <17 years of age

c

European guidelines for endocarditis recommend the addition of gentamicin (3 mg/kg per day in 3 divided doses for 2–4 weeks)